Polyurethane containing a dialkylal-kanolaminoalkylphosphonate



United States Patent POLYURETHANE CONTAINING A DIALKYLAL-KANOLAMINOALKYLPHOSPHONATE Thomas M. Beck, Homewood, and Edward N.Walsh, Chicago Heights, Ill., assignors to Stautfer Chemical Company,New York, -N.Y., a corporation of Delaware W t No Drawing. Originalapplication Mar. 25, 1960, Ser- No. 17,474, now Patent No. 3,076,010,dated Jan. 29, 1963. Divided and this application June 5, 1961, Ser- 15Claims. (Cl. 260-25) This application is a division of our applicationSerial No. 17,474, filed March 25, 1960, now U.S. Patent 3,- 076,010.

p This invention relates to novel dialkylalkanolaminoalkylphosphonatesand to certain c opolymers or reaction products which may be madetherefrom.

In particular this invention relates to certain dialkyldialkanolaminoalkylphosphonates which may be copolymerized or reactedwith isocyanate compounds to render the resulting compositions flameresistant. The resulting flame resistant compositions may be used in theform of expanded foamed products as thermal insulation. By using thetechnique of foaming-in-place such "insulation has found wide use in themanufacture of refrigerators and aircraft components wherein such foamsadd strength as well as flame resistance "to'the components.

The new compounds of this invention may be represented by the generalformula:

R OH

wherein Rand R may be the same or diflerent-alkyl or haloalkyl radicalsand R? and R may be the same or dif-- ferent lower alkylene radicals andR is a lower alkylene radical. a Q

These new compounds may bernade according to the following generalreaction:

I? HNCFUOH): R =o (RO)zPH EXAMPLE 1 Preparation of diethyl N,N-dz'ethano laminomethylphosph onaie To 30.9 g. of diethanolamine wasadded 24.4 g. of aqueous 37% formaldehyde while stirring at 20-30 C. ina reaction flask equipped with thermometer, and dropping funnel. Diethylphosphite, 41.4 g., was then added dropwise while stirring and holdingthe temperature at 2135 C. Both of the above reactions werepropanolamine, dibutanol- "ice exothermic. The reaction mixture was heldat 35 C. with cooling until the exothermic reaction was complete inabout 40 minutes and was then cooled below 30 C. The mixture was furtherstirred at room temperature and then heated to 50 C. for 15 minutes.After cooling it was extracted with 100 ml. of ether and the resultingaqueous phase was then concentrated by distillation under reducedpressure. The residue at 50 C. under 1 mm. pressure was collected as thediethyl N,N liethanolaminomethylphosphonate product. It had an index ofrefraction n =l.4649, weighed 72.5 g. (94.8% yield) and analyzed as12.3% P, 4.9% N (theory 12.2 and 5.5 respectively).

EXAMPLE 2 Preparation of diemthyl N,N-diethan0lamin0methylphosph onateFollowing the procedure of Example 1, 407 g. of aqueous 37% formaldehydewas added to 525 g. of diethanolamine while stirring at 25 C. To theresulting solution was slowly added 550 g. of dimethyl phosphite. Thereaction was exothermic so the temperature was held below 35 C. duringthe addition period of minutes. The reaction mixture was heated to 50 C.for 30 minutes and then cooled. Volatiles were removed under reducedpressure to 80 C. at 1 mm. of mercury. The resulting dimethylN,N-diethanolaminomethylphosphonate weighted 1091.3 g. and analyzed as13.8% P and 5.8% N (theory 13.7 and 6.2).

EXAMPLE 3 Preparation of dibutyl N,N-diethanolaminomeihylphosphomtteFollowing the procedure of Example 1, 407 g. of aqueos 37% formaldehydewas added to 525 g. of diethanolamine while stirring at 20-25 C. To theresulting solution was added 970 g. of dibutyl phosphite while keepingthe temperatureat 25-30 C. The addition took 20 minutes and the mixturewas then stirred without cooling for 69 minutes during which time thetemperature rose to 39 C. It was allowed to stand overnight at roomtemperature, heated to 50 C. and cooled again to room temperature. Waterand volatiles were removed by heating to 50 C. at 2 mm. of mercury togive 1532 g. (98%) of clear, light yellow dibutyldiethanolaminomethylphosphonate. The product analyzed as 4.8% N (theory4.5%).

EXAMPLE 4 Preparation of bis (betachloroethyl)N,N-dieihan0laminomethylphosphonate.

Following the procedure of Example 1, 163 g. of 37% aqueous formaldehydewas added to 210 g. of diethanolamine at 2530 C. in 15 minutes. To theresulting solution 414 g. of bis (betachloroethyl) phosphite was addedat 2030 C. over a 35 minute period. The mixture was stirred at 25-30 C.for 2% hours and then heated to 50 C. for one hour. Water and volatileswere removed by heating to 50 C. at 1 mm. of mercury. The resulting bis(betachloroethyl) diethanolaminomethylphosphonate weighed 622.6 g.(96%), had an index of refraction n =1.5020 and analyzed as 9.2% P and19.8% Cl (theory 9.6 and 21.9).

An outstanding use for these new phosphonate compounds is in providingflame resistance for isocyanate or polyurethane foam formulations. Thephosphonates may be used individually or we have also found that variousmixtures of these new compounds provide excellent flame resistance. Dueto the presence of the hydroxyl groups in the alkanolamine portion ofthe molecule, the compounds actually react with the isocyanates J in theformation of urethane foams to produce flame resistant copolymers orreaction products. In this respect they may replace some or all of thepolyol generally used in such formulations.

The production of urethane or isocyanate polymers is a well-knowncommercial process, see for instance Kirk- Othmer, The Encyclopedia ofChemical Technology, First Supplement, pages 888 et seq. (Interscience1957). Briefly, this process involves the reaction of an isocyanate anda second compound which may contain an hydroxyl, amino or carboxy group,i.e. a compound containing active hydrogen. A preferred group ofcompounds containing active hydrogen are the dior polyfunctional hydroxycompounds. As used in this specification the term isocyanate material isintended to include isocyanate or urethane compositions containingunreacted -NCO radicals.

The most common polymers are formed by the reaction of toluenediisocyanate (hereafter TDI) and a saturated polyester. (This lattercompound may, however, contain benzene unsaturation.) Representativepolyesters are the reaction products of adipic acid and/or phthalicanhydride and ethylene glycol. For purposes of simplicity in thefollowing specification and claims, this type of polyester will beidentified simply by the term phthalicadipic acid type polyester. Othercompounds which may be used in place of the polyesters are polyethers,simple glycols, polyglycols, castor oil, drying oils, etc. Whether theproducts are to be flexible or rigid depends upon the degree ofcross-linking and thus the type of polyol which is used. Since theproducts of this invention may replace only a part of the polyol, theyare thus suitable for use in either flexible or rigid foams.

When an expanded or foamed product is to be produced, it is the generalpractice to add water to the composition. The water reacts with the--NCO groups to release CO and cause theexpansion of the polymer into afoamed mass.

Control of this reaction requires considerable skill and often specialequipment. In some cases it has been found advisable to use inertdissolved gases including the various halohydrocarbons such as thewell-known Freons or Genetrons. These low boiling liquids boil whenwarmed by the heat of reaction and thus cause foaming. They also serveto lower the thermal conductivity and increase the flame resistance ofthe resulting foam. The term foaming agent as used herein is intended toinclude both reactive materials such as water and inert materials suchas halohydrocarbons which cause the reaction products to form anexpanded foam.

In addition to the actual reactants and foaming agents it is alsodesirable in many cases to add a small amount of a surfactant in orderto provide a more homogeneous mixture.

The following examples illustrate the use of our new compounds informing flame resistant polyurethane foamed products.

EXAMPLE 5 To g. of a semi-prepolymer made up of 80 parts toluenediisocyanate (80% being the 2,4 isomer, being the 2,6 isomer) and 20parts of a phthalic-adipic type polyester prepolymer resin (hydroxylnumber 500) were added 12.25 grams of the following mixture:

Diethyl diethanolaminomethylphosphonate (from Example 1) 9.7Trichloromonofluoromethane 2.5

Silicone surfactant (L-521) (as prepared in US.

Patent 2,834,748, Union Carbide and Carbon) 0.05

The mixture was stirred at room temperature in a paper container andallowed to expand. A rigid light yellow foam resulted. It occupied avolume of approximately 250 cc. A small piece of this foam burnedslightly when 4 held in the flame of a Bunsen burner; was immediatelyself-extinguishing when removed from the flame.

EXAMPLE 6 In a manner similar to Example 5, 10 g. of phthalicadipic typeprepolymer and 12 g. of the following mix: ture were mixed together:

Dimethyl diethanolaminomethylphosphonate (Example 2) 84.0Trichloromonofluoromethane 25.0 Silicone surfactant 0.5

The reaction was rapid and the foam expanded to a volume of about 180cc. The foam hardened rapidly and was self-extinguishing.

EXAMPLE 7 In a manner similar to Example 5 the following mixture wasprepared:

- Trichloromonofluoromethane Dibutyl diethanolaminomethylphosphonate(Example 3) 115.0 Silicone surfactant 0.5

14 grams of this mixture and 10 grams of adipic-phthalic type prepolymerwere mixed together and gave a rapid reaction with much swelling. Thefoam did not harden quickly. A piece of the foam was found to be self-Trichloromonofluoromethane extinguishing.

EXAMPLE 8 In a manner similar to Example 5 the following mixture wasprepared:

' G. Bis (betachloroethyl) diethanolaminomethylphosphonate (Example4) 1. 120.0 Silicone surfactant 0.5 25.0

14.5 grams of this mixture and 10 grams of adipic-phthalic' typeprepolymer were mixed and the reaction was initiated with 2 drops oftriethylamine. A slow foaming resulted to give a hard,self-extinguishing foam.

EXAMPLE 9 In a manner similar to Example 5 the following mixture wasprepared:

phthalic type prepolymer were mixed together. About 200 cc. of rigid,self-extinguishing foam was produced.

The preceding examples have been designed to produce primarily rigidfoams. The following example illustrates the production of a flexiblefoam.

EXAMPLE 10 A prepolymer containing 9.5% NCO was first prepared byblending, under dry nitrogen, g. of a polypropylene glycol with amolecular weight of about 2000 and 0.6 g. of water at 40 C. for 20minutes. To this mixture was added 17.7 g. of TDI over a 30 minuteperiod. The temperature rose 6 C. during the addition and was thenraised to C. over a 20 minute period and stirred at that temperature for45 minutes. It was then cooled to 50 C. over a 30 minute period and then12.75 g. of diethyl diethanolamino methylphosphonate and 10.3 g. of TDIwere added. The temperature was then raised to 120 C. over a 30 minuteperiod and stirred for an additional 45 minutes. The prepolymer wascompleted by cooling to 50 0., adding 27.3 g. TDI and stirring for 30minutes at 50 C. It was stored under dry nitrogen.

To prepare the flexible polymer 100 g. of the prepolymer was first mixedwith 0.5 g. of a silicone surfactant at roo-m 'temperature'for 15minutes. Into this mixture was stirred 2.3 g. of Water for one minuteand then it was immediately poured into a 1250 cc. box coated with asilicone mold release. After-15 minutes the expanded foam; was cured at70 C. for 8 hours. It was then removed from the mold, compressed threetimes to /s its total volume and cut into 1 slabs. These slabs werecured 12 hours at 85 C. The'resulting flexible foam had a density of0.10 g./cc. and aphosphorus content of 0.89%.

For purposes of comparison a similar prepolymer containing 9.5% NCO wasprepared from the same polypropylene glycol and TDI using a similarprocess. A flexible foam was then prepared following the above procedureexcept that a mixture of 1.0 g. of N-methyl morpholine and 0.3 g. oftriethylamine was mixed in rapidly just prior to pouring into the mold.A flexible resin with a density of 0.06 g./ cc. resulted.

In order to compare the flame resistance of the two foams x A" x 3"pieces of the foams were suspended vertically and ignited with a Bunsenburner. The phosphorus-free foam ignited readily and burned completelyin 35 seconds. The foam containing diethyldiethanolaminomethylphosphonate was difficult to ignite and required 65seconds to burn completely.

In performing the foregoing examples ordinary commercial grade materialshave been used, with the exception of our new compounds. Thesecommercial compounds are readily available in most instances. This isparticularly true of the aldehydes, ketones, alkanolamines and dialkylphosphites used. In formulating the urethane foams we have used a numberof commercially available polyesters, polyethers, polyols, surfactantsand foaming agents as Well as prepared prepolymer mixtures containingthese compounds. Since it is often diflicult to ascertain the exactcomposition of these commercial compositions, the examples have beenlimited to the use of definitely identified materials.

The exact proportions of reactants necessary to produce the flameresistant reaction products are not too critical. stoichiometricquantities can be readily calculated from the hydroxyl number of thepolyol (or the amount of active hydrogen in the case of amino or carboxygroups) and the number of NCO groups in the isocyanate. Generallyspeaking, however, an excess of isocyanate of 5-15% of thestoichiometric amount is used.

For the purpose of fiameproofing the final reaction product inaccordance with the present invention, we find that it is necessary toadd at least about 3% P and preferably about 4% P in the form of thedialkyl dialkanolaminoalkylphosphonate. Again this may be easilycalculated from the physical constants of the reactants.

We have found it desirable to form a prepolymer by first reacting theTDI with suflicient polyester or polyol to reduce the amount of theremaining NCO groups to about 3035% of the weight of the prepolymer.Since TDI has a normal NCO content of about 48%, the formation of theprepolymer results in reducing the NCO content by about 25%. This isprimarily a process expedient, however, and is not necessary to thepractice of the invention.

The foregoing detailed description is given for clearness ofunderstanding only and no unnecessary limitations should be derivedtherefrom.

\We claim:

1. A reaction product of a dialkyl dialkanolaminoalkylphosphonate, anorganic polyisocyanate and a polyfunctional hydroxy compound.

2. A flame-resistant reaction product comprising organic polyisocyanate,a polyfunctional hydroxy com- 6 pound and adialkyl.dialkanolaminoalkylphosphonate having the formula:

R OH

PRN

R'O RZOH wherein R and R are selected from the group consisting of loweralkyl and lower haloalkyl radicals, R and R are lower alkylene radicalsand R is a lower alkylene radical, in an amount sufiicient to provide atleast about 3% phosphorus in the final reaction product.

4. A flame-resistant reaction product comprising organic polyisocyanate,a polyfunctional hydroxy compound and dimethyldiethanolaminomethylphosphonate in an amount suflicient to provide atleast about 3% phosphor-us in the final reaction product.

5. A flame-resistant reaction product comprising organic polyisocyanate,a polyfunctional hydroxy compound and diethyldiethanolaminomethylphosphonate in an amount sufiicient to provide atleast about 3% phosphorus in the final reaction product.

6. A flame-resistant reaction product comprising organic polyisocyanate,a polyfunctional hydroxy compound and dibutyldiethanolaminomethylphosphonate in an amount sufficient to provide atleast about 3% phosphorus in the final reaction product.

7. A flame-resistant reaction product comprising an organicpolyisocyanate material and bis-(beta-chloroethyl)diethanolaminomethylphosphonate in an amount sufficient to provide atleast about 3% phosphorus in the final reaction product.

8. A flame-resistant reaction product comprising toluene diisocyanateand a substantially stoichiometric amount of a combination of (a) aphthalic adipic acid polyester and (b) a dialkyldialkanolaminoalkylphosphonate having the formula:

PR4N

RO R 011 wherein R and R are selected from the group consistin of loweralkyl and lower haloalkyl radicals, R and R are lower alkylene radicalsand R is a lower alkylene radical, in an amount sufiicient to provide atleast about 3% of phosphorus in the final reaction product.

9. A flame-resistant reaction product comprising toluene diisocyanateand a substantially stoichiometric amount of a combination of (a) aphthalic-adipic acid polyester and (b) dimethyldiethanolaminomethylphosphonate in an amount suificient to provide atleast about 3% of phosphorus in the final reaction product.

10. A flame-resistant reaction product comprising toluene diisocyanateand a substantially stoichiometric amount of a combination of (a) aphthalic-adipic acid polyester and (b) diethyldiethanolaminomethylphosphonate in an amount suflicient to provide atleast about 3% of phosphorus in the final reaction product.

11. A flame-resistant reaction product comprising toluene diisocyanateand a substantially stoichiometric amount of a combination of (a) aphthalic-adipic acid polyester and (b) dibutyldiethanolaminomethylphosphonate in an amount sufficient to provide atleast about 3% of phosphorus in the final reaction product.

12. A flame-resistant reaction product comprisingtoluene diisocyanateand .a substantially stoichiometric amount of a combination of (a) aphthalic-adipic acid polyester and (b) bis-(beta-chloroethyl)diethanolaminomethylphosphonate in an amount sufficient to provide atleast about 3% of phosphorus in the final reaction product.

13. A flame-resistant polyurethane foam comprising the product ofreacting organic polyisocyanate, a polyfunctional hydroxy compound anddialkyl dialkanolarninoalkylphosphonate having the formula:

PRN

RO R OH wherein R and R are selected from the group consisting of loweralkyl and lower haloalkyl radicals, R and R References Cited by theExaminer UNITED STATES PATENTS 2,635,112 4/1953 Fields 26046l.3103,007,884 11/1961 Kaplan et al 2602.5

LEON J. BERCOVITZ, Primary Examiner.

DONALD E. CZAJA, Examiner.

2. A FLAME-RESISTANT REACTION PRODUCT COMPRISING ORGANIC POLYISOCYANATE,A POLYFUNCTIONAL HYDROXY COMPOUND AND A DIALKYLDIALKANOLAMINOALKYLPHOSPHONATE HAVING THE FORMULA: